3,3-Dichlorobenzidine (DCB) is an intermediate in the synthesis of organic pigments, and the proportion of hydrogenation reduction application will increase
3,3-Dichlorobenzidine, referred to as DCB, is an important chlorinated benzidine derivative, which is brown needle-like crystal, easy to oxidize, slightly soluble in water, soluble in alcohols, ethers and dilute acids.
The synthesis process of 3,3-dichlorobenzidine is prepared by using o-nitrochlorobenzene (ONCB) as raw material to obtain o-chloro-oxide azobenzene and o-chlorohydroazobenzene by reduction, and then transposing in acidic medium. There are various reduction processes of 3,3-dichlorobenzidine, including zinc powder method, formaldehyde method, hydrazine hydrate method, hydroreduction method, etc. The hydroreduction method is in an alkaline medium, o-nitrochlorobenzene is reduced to dichlorohydroazobenzene under the action of catalyst (palladium/carbon), and the yield of 3,3-dichlorobenzidine is 90%, which is widely used in United States, Japan, Germany and other countries.
According to the "2024-2029 China 3,3-Dichlorobenzidine (DCB) Industry Market In-depth Research and Development Prospect Forecast Report" released by Xinsijie Industry Research Center, 3,3-dichlorobenzidine (except for hydroreduction process) is one of the highly polluting products in the "Comprehensive List of Environmental Protection (2017 Edition)" and "Comprehensive List of Environmental Protection (2021 Edition)". In order to achieve the goal of carbon peaking and carbon neutrality, chemical projects, especially those with "two highs and one capital", are increasingly tightening the "environmental impact assessment" and "energy assessment" in the approval process, and in this context, the production process of 3,3-dichlorobenzidine will continue to change to the hydroreduction process.
The global production capacity of 3,3-dichlorobenzidine is distributed in Japan, United States, Germany, Korea, France, China and other countries, and the production enterprises include Usu Chemical, Mitsubishi Gas (MGC), Lomac, Germany HF Company, France ICI Company, etc. Among them, Japan is the world's main producer of 3,3-dichlorobenzidine and downstream products.
The mainland is one of the main producers of 3,3-dichlorobenzidine, but the scale of production enterprises is generally small, and with the increasingly stringent environmental protection requirements, the backward production capacity of 3,3-dichlorobenzidine is gradually withdrawing from the market. In terms of projects under construction, there are Xinhua Pharmaceutical (Shouguang) Co., Ltd. with an annual output of 10,000 tons of 3,3-dichlorobenzidine production project, the project environmental protection investment of 15 million yuan, accounting for about 4.15% of the total investment, after completion can reach 10,000 tons/year of 3,3-dichlorobenzidine hydrochloride, 2,000 tons/year of 2,2-dichlorooxide azobenzene, 1,500 tons/year of 2,2-dichlorohydroazobenzene, 600 tons/year of o-chloroaniline.
3,3-Dichlorobenzidine is an important organic pigment intermediate, which is widely used in paints, rubber, plastics, inks, coatings, crayons, pharmaceuticals and textiles. 3,3-Dichlorobenzidine mainly produces diclobenzidine organic pigments, and the output of organic pigments prepared by it accounts for about a quarter of the total output of organic pigments. In 2023, the output of organic pigments in mainland China will be about 255,000 tons, and the market size will reach more than 8.2 billion yuan.
Industry analysts said that 3,3-dichlorobenzidine is an important synthetic intermediate of organic pigments, and with the development of downstream industries, the market demand for 3,3-dichlorobenzidine will continue to be released. 3,3-Dichlorobenzidine has the problem of decomposing potential carcinogens at high temperatures, and with the improvement of safety requirements and the iteration of organic pigment technology, 3,3-Dichlorobenzidine is also at risk of being replaced by other high-performance, high-safety and green intermediates.